NFPA Compliance and Electrical Transformers

Published: 26th March 2010
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Even though energy transformers typically deal with hazardous levels of electricity, they are often located in or near fairly public places. Their safety is thus a matter of much concern. For this reason, requirements for electrical transformers and employees working with them are included in NFPA 70 and 70E.

All electrical wiring and equipment has to be in accordance with NFPA 70. With electricity being hazardous, employees working with transformers are also subject to protection in accordance with 70E, unless it is an existing installation, which may be permitted to continue in service, subject to approval by the authority having jurisdiction over it.

Below are some of the key provisions relative to transformers mentioned in NFPA 70:

Individual dry-type transformers of more than 112½ kVA rating should be installed in a transformer room of fire-resistant construction having a minimum fire rating of 1 hour. Transformers not over 112½ kVA have no specific installation requirements for the room in which they are located.

Dry-type transformers rated over 35,000 volts should be installed in a vault with minimum fire resistance of 3 hours. Each doorway leading into a vault from the building interior should have a tight fitting door that has a minimum fire rating of 3 hours. Exception: Where transformers are protected with automatic sprinkler, water spray, carbon dioxide, or halon, construction of 1-hour rating shall be permitted.

About NFPA 70E

The NFPA 70E standard addresses the electrical safety requirements for all employees who install, maintain and repair electrical systems. It recognizes the hazards associated with the use of electrical energy and includes guidelines to take precautions against injury or death.

Compliance to NFPA 70E requires that all personnel working on electrical equipment operating at >50V should wear arc-flash protective garments to prevent injury. Arc-flash is an electric current that passes through the air when the insulation between electrified conductors can no longer withstand an applied voltage. A flash can last less than a second and its results can be severe and even lead to fatalities.

NFPA 70E Compliance Checklist

Implementation of NFPA 70E regulations is a major challenge. The arc flash analysis requires training and tools to implement the program.

Below is a checklist to establish NEPA 70E Compliance

Short-Term Action

* Electricians, maintenance mechanics and facilities repair workers are not to work on hot/live equipment wearing all-cotton clothing

* Electricians, maintenance mechanics and facilities repair workers should work as much as possible on de-energized equipment.

* Employees are to use interim hazard warning labels on electrical equipment.

Long-Term Action

* Electrical workers are to be trained in Arc-flash Hazard Awareness.

* Existing Logout/Tagout (LOTO) procedures are to be periodically reviewed to make certain they include all control panels.

* The LOTO training of previous employees to be assessed to determine if they need to be retrained.

* Periodic tool audits to be conducted to ensure employees have the required tools for their safety and replacement of missing tools.

* Reviewing those employees have clothing appropriate for electrical work.

* Arc-flash hazard analysis to be conducted to determine flash protection boundary on switchboards, panel boards, industrial control panels, motor control centers, other similar equipment.

So if you are planning to buy a transformer, you might want to ensure your transformer is NFPA 70 and 70E compliant, and pay some special attention to transformer security and safety of employees working with them.

Pacific Crest Transformers, with its years of experience on safety, advises those buying transformers from them on how to comply by the required legislation, so that risk of any kind is minimized.

To know more about Electrical transformers check out Pacific crest transformers website.

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